EX-4.3


       N U M B E R                                            U N I T S

   PRO.U

                                [SMARTPROS LOGO]

INCORPORATED UNDER THE LAWS OF
    THE STATE OF DELAWARE
                                                          CUSIP 83171G 30 1


                                 SMARTPROS LTD.

EACH UNIT CONSISTING OF TWO SHARES OF COMMON STOCK,  AND ONE WARRANT TO PURCHASE
ONE SHARE OF COMMON STOCK
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THIS CERTIFIES THAT














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or registered assigns,  (the "Registered  Holder") is the owner of the number of
Units  specified  above.  Each Unit  consists of two (2) shares of common stock,
$.0001 par value (the "Common Stock"), of SmartPros Ltd. (the "Company") and one
(1) redeemable warrant (the "Warrant") to purchase one share of Common Stock for
$ per share (subject to adjustment)  until 5:00 p.m. Eastern Time ________.  The
Units will trade on the American Stock  Exchange  until the Separation  Date (as
defined  below).  Until the  Separation  Date,  neither the Common Stock nor the
Warrants will trade  separately.  On the  Separation  Date, the Units will cease
trading and the Common Stock and the Warrants will begin trading on the American
Stock  Exchange.  The  Separation  Date will be the tenth  (10th)  business  day
following  the date on which  Paulson  Investment  Company,  Inc.  notifies  the
Company and the  American  Stock  Exchange  that trading in the Common Stock and
Warrants will Commence. The Separation Date may not be earlier than the 31st day
or later than the 45th day  following the date hereof (the  "Separation  Date").
The  Warrants  underlying  the Units are issued  under and pursuant to a certain
Warrant Agreement dated as of (the "Warrant Agreement"), between the Company and
American Stock Transfer & Trust Company, as Warrant Agent (the "Warrant Agent"),
and are subject to the terms and provisions contained therein and on the face of
the  certificates  covered  thereby,  to all of which terms and  provisions  the
holder of this Unit  Certificate  consents  by  acceptance  hereof.  The Warrant
Agreement  provides for adjustment in the number of shares of Common Stock to be
delivered upon the exercise of the Warrant  evidenced hereby and to the exercise
price of such Warrant in certain events therein set forth.

Copies of the  Warrant  Agreement  are  available  for  inspection  at the stock
transfer  office of the Warrant  Agent or may be obtained  upon written  request
addressed  to the  Company  at 12  Skyline  Drive,  Hawthorne,  New York  10532,
Attention: Chief Executive Officer.

This Unit  Certificate is not valid unless  countersigned  by the Transfer Agent
and Registrar of the Company.

Dated:


                                  SMARTPROS LTD.

                                    CORPORATE
       -------------------                              -------------------
        SIGNATURE TO COME             SEAL               SIGNATURE TO COME
       -------------------            1999              -------------------

                                     DELAWARE


           SECRETARY                                      VICE CHAIRMAN OF
                                                          THE BOARD OF
                                                          DIRECTORS





COUNTERSIGNED AND REGISTERED:
 AMERICAN STOCK TRANSFER & TRUST COMPANY
                          TRANSFER AGENT
                           AND REGISTRAR
BY


                      AUTHORIZED OFFICER

<PAGE>

                                 SMARTPROS LTD.

       The  Registered  Holder hereby is entitled,  at any time, to exchange the
Units  represented  by this Unit  Certificate  for Common  Stock  Certificate(s)
representing  two shares of Common Stock, for each Unit represented by this Unit
Certificate and one Warrant Certificate  representing one Warrant, for each Unit
represented by this Unit Certificate, upon surrender of this Unit Certificate to
the Transfer Agent,  Warrant Agent and Registrar together with any documentation
required by such agent.

REFERENCE IS MADE TO THE WARRANT AGREEMENT  REFERRED TO ON THE FACE HEREOF,  AND
THE  PROVISIONS OF SUCH WARRANT  AGREEMENT  SHALL FOR ALL PURPOSES HAVE THE SAME
EFFECT AS THOUGH FULLY SET FORTH ON THE FACE OF THIS CERTIFICATE.  COPIES OF THE
WARRANT  AGREEMENT MAY BE OBTAINED UPON WRITTEN  REQUEST FROM THE WARRANT AGENT,
TRANSFER AGENT AND REGISTRAR, AMERICAN STOCK TRANSFER & TRUST COMPANY.

       The following abbreviations,  when used in the inscription on the face of
this  certificate,  shall be  construed  as though they were written out in full
according to applicable laws or regulations.

<TABLE>
<S>                                            <C>
TEN COM   - as tenants in common               UNIF GIFT MIN ACT- _______ Custodian ________
TEN ENT   - as tenants by the entireties                          (Cust)             (Minor)
JT TEN    - as joint tenants with right of           under Uniform Gifts to Minors Act
            survivorship and not as tenants          _________________________________
            in common                                              (State)

COM PROP  - as community property              UNIF TRF MIN ACT-  _______ Custodian ________
                                                                   (Cust)             (Minor)
                                                   under Uniform Transfers to Minors Act
                                                     _________________________________
                                                                   (State)
</TABLE>


                               FORM OF ASSIGNMENT
                      (TO BE SIGNED ONLY UPON ASSIGNMENT)


FOR VALUE RECEIVED, the undersigned Registered Holder (_______________________ )

 PLEASE INSERT SOCIAL SECURITY OR OTHER
IDENTIFICATION NUMBER OF REGISTERED HOLDER

__________________________________________


__________________________________________

hereby sells, assigns and transfers unto _______________________________________

________________________________________________________________________________
               (Please Print Name and Address including Zip Code)

________________________________________________________________________________

________________________________________________________________________________

___________________________________________________________________________Units
evidenced  by the within  Unit  Certificate,  and  irrevocably  constitutes  and
appoints

________________________________________________________________________________

________________________________________________________________________Attorney
to transfer this Unit  Certificate  on the books of SmartPros Ltd. with the full
power of substitution in the premises.


Dated, _________________________


                   SIGNATURE: __________________________________________________

                              (Signature  must  conform in all  respects  to the
                              name of Registered Holder as specified on the face
                              of this  Unit  Certificate  in  every  particular,
                              without alteration or any change  whatsoever,  and
                              the  signature   must   guaranteed  in  the  usual
                              manner.)



        SIGNATURE GUARANTEED: __________________________________________________

                              The signatures should be guaranteed by an eligible
                              institution (banks, stockbrokers, savings and loan
                              association  and credit unions with  membership in
                              an approved signature medallion program), pursuant
                              to S.E.C. Rule 17Ad-15.